[resolved] Is there a way to delete all comments at once? (7 posts)

I have over 1,600 comments that are spam on my site. I have just installed Akismet, so I think that should solve the problem of future spam, but how do I get rid of the 1,600 comments? It seems I can only delete 20 at a time, which means I will have to do it 80 times. Is there anyway to delete the whole 1,600 at one time?